A conventional digital to analog conversion (DAC) circuit includes a plurality of P-type metal oxide semiconductor field effect transistors (pMOSFETs) and a plurality of N-type metal oxide semiconductor field effect transistors (nMOSFETs), and has the following disadvantages.
1. The total number of the pMOSFETs is equal to the total number of the nMOSFETs. Therefore, the conventional DAC circuit uses a large number of MOSFETs, and occupies a large area.
2. All of the bulk terminals of the pMOSFETs receive the most positive voltage, and all of the bulk terminals of the nMOSFETs receive the most negative voltage. Therefore, most of the pMOSFETs and most of the nMOSFETs have significant body effects and large ON resistances.
3. For each of the pMOSFETs and the nMOSFETs, when the MOSFET is to transmit a voltage with a magnitude that is approximately the voltage magnitude of the signal received at its gate terminal, it is hard for the MOSFET to conduct.